Makes perfect sense - I was assuming (erroneously) that the module exit
routine WAS within the non-root domain and you could use the shorthand
form. I have put in the explicit form:
adeos_catch_event_from(&domain_desc,event,NULL)
and this works great - I also note that you say it is unecessary; I just
wanted to verify your theory.
Thanks for your help,
Currie
On Thu, 14 Oct 2004, Philippe Gerum wrote:
> On Thu, 2004-10-14 at 20:13, Currie Reid wrote:
> > Hello Philippe,
> >
> > The patch works, but raises one or two questions (sorry!). First, I
> > understood what you meant about the disappearing handler crashing the box,
> > so what I did in the root level domain is on module unloading I reset the
> > handler to null -
> >
> > static void __exit my_cleanup( void ){
> >
> > adeos_catch_event( ADEOS_EXIT_PROCESS, 0 );
> > adeos_unregister_domain( &domain_desc );
> > }
> >
> > which works in the root domain. So I figured that this might be a proper
> > clean-up procedure in higher priority domains. So I did the same thing in
> > the module cleanup routine when registering a domain for the same event.
> > When this module is unloaded, the handler does not default back to the
> > root domain handler. Without the cleanup, it works as I would have
> > expected, but if I reset the handler in the higher priority domain, it
> > seems to wipe out the handler further down the pipe. Again, I don't know
> > if this is intended behaviour, but I would have thought that setting the
> > event handler in a higher priority domain to null would have no affect on
> > lower priority (or root) domains. These lower priority domains would
> > retain the handler attributed to them at the time of their entry.
> >
>
> First guess: maybe because you are using adeos_catch_event() to nullify
> it, which implicitely does
> adeos_catch_event_from(adp_current,event,NULL) [i.e. it's a shorthand] ,
> and on behalf of a module cleanup routine, adp_current == adp_root, i.e.
> Linux?
>
> So, if you want to clean it up at the most prioritary level, you have to
> write adeos_catch_event_from(&domain_desc,event,NULL), this way, the
> current domain (Linux) won't be implicitely used for the operation.
>
> However, unregistering a domain (now) properly releases all events for
> it since the stage it occupies disappears, so you don't need to clear
> the event handlers manually for this domain.
>
> > Currie
> >
> >
> > On Thu, 14 Oct 2004, Philippe Gerum wrote:
> >
> > > On Thu, 2004-10-14 at 15:41, Currie Reid wrote:
> > > > Hello all,
> > > >
> > > > I am just trying to understand the underlying behaviour of adeos, and in
> > > > my testing I have come across some behaviour that I want to verify is
> > > > correct. If I set a handler for ADEOS_EXIT_PROCESS without registering
> > > > a
> > > > domain, then the handler is in the root domain and behaves as expected
> > > > (thank you printk!). Next, I do a handler in a registered domain for
> > > > ADEOS_EXIT_PROCESS and perform 2 tests - 1 where the handler doesn't
> > > > propagate the event to the root domain, and one where it does. These
> > > > both
> > > > behave as expected - when propagated, I see the handler executing once
> > > > for
> > > > each domain. But when I unload the module and unregister the domain,
> > > > the
> > > > handler in the root domain no longer executes - I would have thought
> > > > that
> > > > the handler would still be in place.
> > > >
> > > > If I register 2 domains and duplicate the test, when the higher priority
> > > > domain is unregistered, the lower priority domain starts handling the
> > > > events again, as expected. I haven't delved into to code to see how
> > > > easy
> > > > this is to change - mostly because I'm not sure that this isn't
> > > > uninitended behaviour.
> > > >
> > >
> > > Actually, this is. I mean: a bug. Please try applying the following
> > > patch to adeos/generic.c and let me know of the outcome. This said, keep
> > > in mind that fixing this bug will make your box crash if you intend to
> > > keep a handler attached which ends up disappearing from the address
> > > space after the module is unloaded.
> > > Thanks for the report.
> > >
> > > --- generic.c 4 Oct 2004 17:34:19 -0000 1.17
> > > +++ generic.c 14 Oct 2004 16:24:53 -0000
> > > @@ -173,7 +173,7 @@
> > >
> > > for (event = 0; event < ADEOS_NR_EVENTS; event++)
> > > /* Need this to update the monitor count. */
> > > - adeos_catch_event(event,NULL);
> > > + adeos_catch_event_from(adp,event,NULL);
> > >
> > > #ifdef CONFIG_SMP
> > > {
> > > --
> > >
> > > Philippe.
> > >
> > >
> >
> >
> > _______________________________________________
> > Adeos-main mailing list
> > [email protected]
> > https://mail.gna.org/listinfo/adeos-main
> --
>
> Philippe.
>
>
